x86: allow number of additional hotplug CPUs to be set at compile time, V2

The default number of additional CPU IDs for hotplugging is determined
by asking ACPI or mptables how many "disabled" CPUs there are in the
system, but many systems get this wrong so that e.g. a uniprocessor
machine gets an extra CPU allocated and never switches to single CPU
mode.

And sometimes CPU hotplugging is enabled only for suspend/hibernate
anyway, so the additional CPU IDs are not wanted. Allow the number
to be set to zero at compile time.

Also, force the number of extra CPUs to zero if hotplugging is disabled
which allows removing some conditional code.

Tested on uniprocessor x86_64 that ACPI claims has a disabled processor,
with CPU hotplugging configured.

("After" has the number of additional CPUs set to 0)
Before: NR_CPUS: 512, nr_cpu_ids: 2, nr_node_ids 1
After: NR_CPUS: 512, nr_cpu_ids: 1, nr_node_ids 1

[Changed the name of the option and the prompt according to Ingo's
 suggestion.]
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The flag_is_changeable_p() is used by
has_cpuid_p() which can return different results
in the code sequence below:

 if (!have_cpuid_p())
      identify_cpu_without_cpuid(c);

  /* cyrix could have cpuid enabled via c_identify()*/
  if (!have_cpuid_p())
      return;

Otherwise, the gcc 3.4.6 optimizes these two calls
into one which make the code not working correctly.

Cyrix cpus have the CPUID instruction enabled before
the second call to the have_cpuid_p() but
it is not detected due to the gcc optimization.
Thus the ARR registers (mtrr like) are not detected
on such a cpu.
Signed-off-by: NKrzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Currently the low-level function to dump user-passed registers on i386 is
called __show_registers() whereas on x86-64 it's called __show_regs(). Unify
the API to simplify porting of kmemcheck to x86-64.
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
Acked-by: NVegard Nossum <vegard.nossum@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Add functions that use the infrastructure added by the x2apic code. These
functions were originally stubbed out since the UV code went into the
tree prior to the x2apic code.
Signed-off-by: NJack Steiner <steiner@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Commit 4a701737 ("x86: move prefill_possible_map calling early, fix")
is the wrong fix: prefill_possible_map() needs to be available
even when CONFIG_HOTPLUG_CPU is not set. A followon patch will do that.

Fix this correctly by making prefill_possible_map() available even when
CONFIG_HOTPLUG_CPU is not set. The function is needed so that
the number of possible CPUs can be determined.

Tested on uniprocessor machine with CPU hotplug disabled.

From boot log:
  Before: NR_CPUS: 512, nr_cpu_ids: 512, nr_node_ids 1
  After: NR_CPUS: 512, nr_cpu_ids: 1, nr_node_ids 1
Signed-off-by: NChuck Ebbert <cebbert@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The Winchip-2 and Winchip-2A cpu choices select the
same options for kernel and compiler.

Merge them to save few bytes and reduce confusion.
Signed-off-by: NKrzysztof Helt <krzysztof.h1@wp.pl>
Acked-by: NH. Peter Anvin <hpa@zytor.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Fix the size of the mappings of UV hub registers. Size must
be a function of the maximum node number within the SSI.
Signed-off-by: NJack Steiner <steiner@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

also change two functions to static.
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This patch hardcodes which traps should be forwarded to
handle_vm86_trap in do_trap. This allows to remove the
vm86 parameter from the i386-version of do_trap, which
makes the DO_VM86_ERROR and DO_VM86_ERROR_INFO macros
unnecessary.

x86_64 part is whitespace only.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The last use of trace_hardirqs_fixup is unnecessary, because the
trap is taken with interrupt off on i386 as well as x86_64, and
the irq-tracer is notified of this from the assembly code.

trace_hardirqs_fixup and trace_hardirqs_fixup_flags are removed
from include/asm-x86/irqflags.h as they are no longer used.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

All exceptions are taken via interrupt gates. TRACE_IRQS_OFF
is called just before entering the C code, so the irq state
is known to the irq tracer at this point. No need to call
trace_hardirqs_fixup.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

All exceptions are taken via interrupt gates. TRACE_IRQS_OFF
is called just before entering the C code, so the irq state
is known to the irq tracer at this point. No need to call
trace_hardirqs_fixup.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

All exceptions are taken via interrupt gates. TRACE_IRQS_OFF
is called just before entering the C code, so the irq state
is known to the irq tracer at this point. No need to call
trace_hardirqs_fixup.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Add TRACE_IRQS_OFF just before entering the C code.

All exceptions are taken via interrupt gates. If irq tracing is
enabled, it should be notified as soon as possible. Interrupts
are only (conditionally) re-enabled in C code.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Add TRACE_IRQS_OFF just before entering the C code.

All exceptions are taken via interrupt gates. If irq tracing is
enabled, it should be notified as soon as possible. Interrupts
are only (conditionally) re-enabled in C code.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Portions of the ACPI code needs to know if a system is a UV system prior
to genapic initialization. This patch adds a call early_acpi_boot_init()
so that the apic type is discovered earlier.

V2 of the patch adding fixes from Yinghai Lu.
Much cleaner and smaller.
Signed-off-by: NJack Steiner <steiner@sgi.com>
Acked-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Take it out of time initialization and move it to
cpu detection time.
Signed-off-by: NGlauber Costa <glommer@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Only test for MCA_bus if support for MCA is compiled in.
Also, for x86_64, write the code inside the conditional
for consistency with i386. It won't bite us, since it'll
probably never select CONFIG_MCA anyway.
Signed-off-by: NGlauber Costa <gcosta@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Replace "4" in time_32.c code by sizeof(long).
This way, it can work on x86_64 too.
Signed-off-by: NGlauber Costa <gcosta@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NGlauber Costa <gcosta@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NGlauber Costa <gcosta@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Provide apic_intr_init and smp_intr_init functions.
Signed-off-by: NGlauber Costa <gcosta@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NGlauber Costa <gcosta@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

For x86_64, it does not really matter. But makes the
code equal to i386.
Signed-off-by: NGlauber Costa <gcosta@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Signed-off-by: NGlauber Costa <gcosta@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Save rbp twice: One is for marking the stack frame, as usual (already
there), and the other, to fill pt_regs properly. This is because bx
comes right before the last saved register in that structure, and not
bp. If the base pointer were in the place bx is today, this would not
be needed.
Signed-off-by: NGlauber Costa <gcosta@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Coalesce v8086_mode and user_mode into a single
user_mode_vm() test.
Signed-off-by: NGlauber Costa <gcosta@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Instead of using SEGMENT_IS_KERNEL_CODE, use the
"user_mode" macro, which can play the same role. Delete
the former, since it now lacks any user.
Signed-off-by: NGlauber Costa <gcosta@redhat.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Some CPUs have vendor string in the middle of model_id instead of beginning
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Since pte_flags() is much cheaper than pte_val() in some virtualized
environments (namely, Xen), use the former whereever possible.
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Cc: "Nick Piggin" <npiggin@suse.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

When nr_range gets decremented, the same slot must be considered for
coalescing with its new successor again.

The issue is apparently pretty benign to native code, but surfaces as a
boot time crash in our forward ported Xen tree (where the page table
setup overall works differently than in native).
Signed-off-by: NJan Beulich <jbeulich@novell.com>
Acked-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

We should check if we have ESR register before reading from it.
Signed-off-by: NCyrill Gorcunov <gorcunov@gmail.com>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

it's useful for debugging purposes to know the location of the EBDA.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

v2: use __acpi_unmap_table()
Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The check prevents flags on mappings from being changed, which is not
desireable.  There's no need to check for replacing a mapping, and
x86-32 does not do this check.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The remappings in setup.c are all just ordinary memory, so use
early_memremap() rather than early_ioremap().
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

early_ioremap() is also used to map normal memory when constructing
the linear memory mapping.  However, since we sometimes need to be able
to distinguish between actual IO mappings and normal memory mappings,
add a early_memremap() call, which maps with PAGE_KERNEL (as opposed
to PAGE_KERNEL_IO for early_ioremap()), and use it when constructing
pagetables.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Use one of the software-defined PTE bits to indicate that a mapping is
intended for an IO address.  On native hardware this is irrelevent,
since a physical address is a physical address.  But in a virtual
environment, physical addresses are also virtualized, so there needs
to be some way to distinguish between pseudo-physical addresses and
actual hardware addresses; _PAGE_IOMAP indicates this intent.

By default, __supported_pte_mask masks out _PAGE_IOMAP, so it doesn't
even appear in the final pagetable.
Signed-off-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The exception handlers in entry_32.S should now all call
TRACE_IRQS_OFF before calling the C code. The calls to
trace_hardirqs_fixup should now be unnecessary. Remove them.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

At this point interrupts are off, so let's inform the tracing
code of that fact before calling into C.
Signed-off-by: NAlexander van Heukelum <heukelum@fastmail.fm>
Signed-off-by: NIngo Molnar <mingo@elte.hu>